A second man has died of pneumonic plague in northwest China, in an outbreak that prompted authorities to seal off an entire town where about a dozen people were infected with the highly contagious deadly lung disease, a state news agency said.

The man who died Sunday was identified only as 37-year-old Danzin from Ziketan, the stricken town in Qinghai province, the official Xinhua News Agency said.

Danzin was a neighbor of the first person who died, a 32-year-old herdsman whose name was not given. Another 10 people, mostly relatives of the first deceased man, were infected and undergoing isolated treatment in hospital, Xinhua said in a report late Sunday.

The town of 10,000 people has been placed under quarantine and a team of experts was being sent to the area, it said. The local health bureau warned Sunday that anyone with a cough or fever who has visited the town since mid-July should seek treatment at a hospital.

Pneumonic plague is spread through the air and can be passed from person to person through coughing, according to the World Health Organization. It is caused by the same bacteria that occurs in bubonic plague — the Black Death that killed an estimated 25 million people in Europe during the Middle Ages.

While bubonic plague — which is usually transmitted by flea bite — can be treated with antibiotics if diagnosed early, pneumonic plague is one of the deadliest infectious diseases. According to the WHO, humans can die within 24 hours of infection.